JPS62281538A - Network connection method - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [) Already required] Collision detection and detection of path type local area network (hereinafter referred to as bus type LAN) using carrier sense multiple access collision detection method (hereinafter referred to as C5MA/CD method) When connecting a transceiver that detects the presence or absence of a carrier to a henoda adapter that aggregates data from a C3MA/CD star local area network (hereinafter referred to as star LAN) and detects collisions and detects the presence or absence of a carrier, the star A network that detects collisions between data from a LAN and a bus LAN, and when a collision is detected, notifies the data sending side of the collision, and when no collision is detected, sends the data to its destination. Connection method.

[Industrial application field]

The present invention is a CSMA/CD system lotus type LAN.
and a star-type LAN.

A lotus type LAN with a transmission rate of 1Mbps and a star type LAN with a transmission rate of 1Mbps using the CS MA/CD system were standardized as RSO and IEEE 802.3 in 1985.

In the C3MA/CD method, a station that has issued a transmission request first monitors the common transmission path, checks whether or not another station is transmitting (carrier sense), and if it is in use, waits for transmission. , if it is free, send the data.

Such operations are performed by multiple stations simultaneously using a common transmission path (multiple access). However, simply checking the availability of the common transmission path will cause collisions if multiple stations send frames at the same time, and normal frames will not be delivered to their destinations.

Therefore, each station monitors the presence or absence of a collision during transmission (collision detection), and when a collision is detected, stops transmission, waits for a certain period of time, and then repeats the same procedure again for retransmission.

An overview of one example of a standardized C3MA/CD system is explained using Fig. 4.The lotus-shaped L shown in (A)
In the AN, transceivers 6 and 7, which detect collisions and the presence or absence of carriers, are connected to a LAN adapter 21 which controls the protocol of the network of terminals 13 and 14 that perform data communication, respectively.

On the other hand, the transceiver 8 is for connection to a star-type LAN, and these are usually connected by a coaxial cable or an optical fiber, and the transmission speed is 1OMbps.

The star-shaped LAN shown in (B) centralizes terminals 15 to 20 that perform data communication, and hubs 10 to 12 that detect collisions and detect the presence or absence of carriers. They are connected in a tree shape through a header hub 9, and the hubs 10-12 and terminals 15-20 are connected by providing each terminal with a LAN adapter 22 that controls the network protocol.

If this lotus-shaped LAN and star-shaped LAN can be connected, for example, files on a lotus-shaped LAN terminal can be accessed from a star-shaped LAN terminal, or a bus-shaped LAN can be connected.
This makes it possible to send e-mails all at once from terminals on the star LAN to terminals on the star LAN.
It is desired that connections between N.

[Problems to be solved by conventional technology and invention] Conventionally,
As a connection method for C5MA/CD type LAN, there is a bridge method that connects bus-type LANs, but a method for connecting lotus-type LAN and star-type LAN has not been developed and it was not possible to connect them. .

[Means for solving problems]

As shown in the principle block diagram of FIG. 1, the above problem is solved by a speed conversion section 4 for data speed conversion between the helical LAN and the star LAN, the transceiver, and the header hub on the bottom hub side of the star LAN. More data from each LA
Address decoder 1 that distributes data to and from N
A collision between these sorted data is checked, and if no collision occurs, the data for the star-shaped LAN is sent to the header hub, and the data for the lotus-shaped LAN is sent to the transceiver via the speed converter 4. If a collision is detected, this problem can be solved by the network connection system of the present invention, which includes a collision detection section 2 that sends a collision detection signal to the LAN that sent the data to be transmitted to the other party.

[Effect]

According to the present invention, the difference in transmission speed between the bus type LAN and the star type LAN is adjusted by the speed converter 4, and the difference in transmission speed between the bus type LAN and the star type LAN is
And whether the data from the star LAN is directed to your own LAN or to another L
Address decoder 1 determines whether it is for AN or not.
Collision detection of these distributed data is performed by the collision detection unit 2, and when a collision occurs, the data to be sent to the other LAN is notified to the LAN where the collision occurred, thereby enabling connection. ing.

〔Example〕

FIG. 2 is a block diagram of an embodiment of the present invention, and FIG. 3 is a block diagram of an embodiment of the present invention.
FIG. 3 is a diagram showing a specific example of the collision detection circuit shown in the figure.

In the figure, 9' is a header hub, 23, 28, 29, and 30 are collision detection circuits, 24 is a collision detection signal generator, 25 is a signal connection part for sending the signal from the bridge 40 to the header hub 9',
26 and 27 are address decoders that distribute input data inside and outside of each LAN, 31 is a jam pattern creation unit that creates a jam pattern to notify the bus type LAN of a collision, and 32 is a block from the star type LAN for adjusting the transmission speed. First-in-first-out (F (FO) memory,
33 is a buffer for taking in data from the bus-type LAN and outputting it to the star-type LAN in order to adjust the transmission speed, 34 is a serial interface adapter, and 40 is a bridge.

The header hub 9” of the star type LAN is the hub 10 in Fig. 4.
12 is input to the collision detection circuit 23, and if a collision is detected, a signal is sent to the collision detection signal generation section 24 to generate a collision detection signal, and the data is sent to each hub 10 via the connection section 25.
~ Send to 12.

If a collision is not detected, the data is inputted to the address decoder 26, data SIN in the star type LAN is sent to the collision detection circuit 30, and data 5O for the path type LAN is inputted to the address decoder 26.
UT is sent to a collision detection circuit 28.29.

On the other hand, human input data RD from the bus type LAN is once taken into the buffer 33 via the serial interface adapter 34 and then output, and inputted to the address decoder 27, and data EIN in the bus type LAN is input to the collision detection circuit 28.
Data for star type LAN is collision detection circuit 29.30
sent to.

Further, the collision detection signal CD detected within the bus type LAN passes through the serial interface adapter 34 and is sent to the collision detection circuit 28.
．． 29 is input.

The collision detection circuits 28, 29, and 30 are shown in (A) and (B) in Fig. 3.
This circuit implements the logic shown in (C).

The collision detection circuit 28 uses a bus type LAN as shown in (A).
Data 5 OUT for and data EI in bus type LAN
If the collision detection signal CD from within the N and lotus type LAN is input and no collision is detected, the data 5OUT for the bus type LAN is sent to the FIF○ memory 32 as data SD, and the two data overlap and a collision is detected. If so, the collision detection signal CD is sent to the collision detection signal generating section 24, and the interior of the star-shaped LAN is notified of this fact.

In this case, all data is sent from the transceiver 8 of the bus-type LAN in Fig. 4 regardless of whether it is related or not, so the data EIN in the bus-type LAN is necessary for collision detection, but it cannot be taken out as output. I don't have to take it out because I don't need it.

The collision detection circuit 29 uses a lotus-shaped LAN as shown in (B).
Data 5OUT for LAN and Data E for star type LAN
OUT and the collision detection signal CD from the bus-type LAN are input, and if no collision is detected, the data 5OUT for the lotus-type LAN is input to the FIFO memory 32 as the data SD for the lotus-type LAN, and then the data 5OUT for the lotus-type LAN is inputted to the FIFO memory 32 as the data SD for the lotus-type LAN. The data E01JT for the star type LAN is sent to the connection unit 25 as the data ED for the star type LAN, and is sent out into the star type LAN.

If two pieces of data overlap and a collision is detected, a collision detection signal CD is sent to the star-type LAN via the connection unit 25, and is also sent to the jam pattern creation unit 31, where a jam pattern is created and stored in the FIFO memory. 32 will be manned.

In the collision detection circuit 30, as shown in (C), the star-shaped LA
Data SIN in N and data E for star LAN
If OUT is input and there is no collision, data is sent to the star LAN via the connection unit 25 as data ED for the star LAN.
When the two data overlap and a collision is detected, the jam pattern creation unit 31 outputs the collision detection signal CD as a collision detection signal CD.
A jam pattern is created and stored in F, IFO memory 3.
Enter 2.

When the data stored in the FIF○ memory 32 reaches a certain amount, it is sequentially sent to the path type LAN via the serial interface adapter 34.

In this way, when transferring data between the star type LAN and the bus type LAN, the difference in transmission speed is adjusted by using the FIFO memory 32 and the buffer 33.
Furthermore, if a collision is detected, the data to be sent to the other LANs is notified to the LAN where the collision occurred, thereby enabling a network connection system between the star-type LAN and the lotus-type LAN.

〔Effect of the invention〕

As explained in detail above, according to the present invention, the star-shaped LA
When transferring data between N and bus-type LAN, differences in transmission speeds are adjusted through first-in, first-out memory and buffers, and if a collision is detected, each L'
By notifying the LAN side that generated the data to be sent to the AN side, there is an effect that network connection between the star type LAN and the bus type LAN can be established.

[Brief explanation of the drawing]

Figure 1 is a schematic diagram of the principle of the present invention, Figure 2 is a block diagram of an embodiment of the present invention, and Figure 3 is a block diagram of the embodiment of the present invention.
FIG. 4 is a block diagram illustrating an overview of the system. In the figure, 1.26.27 is an address decoder, 2.23.28, 29.30 is a collision detection circuit, and f731
4 is a jam pattern creation section, 4 is a speed conversion section, 9.9 is a header hub, 24 is a collision detection signal generation section, 33 is a buffer, 34 is a serial interface adapter, and 40 is a bridge. 1. Data available for 2 yen. ! ! -Figure 3

Claims (1)

[Claims] A transceiver for detecting collisions and the presence or absence of a carrier in a bus type local area network using a carrier sense multiple access collision detection method, and a star type transceiver using a carrier sense multiple access collision detection method. When connecting with a header hub that aggregates local area network data, detects collisions, and detects the presence or absence of a carrier, a speed converter (4) for data speed conversion between the bus type local area network and the star type local area network is used. ) and an address decoder (1) that distributes the data from the transceiver and the header hub as data into and out of each local area network.A collision between these distributed data is checked, and if no collision occurs, a star type Data for the local area network is sent to the header hub, data for the bus-type local area network is sent to the transceiver via the speed converter (4), and when a collision is detected, data to be sent to the other party is sent. A network connection system characterized in that the local area network is provided with a collision detection unit (2) that sends a collision detection signal to a bus-type local area network.